Many firearms have adjustable sights so that the sights can be adjusted to enable the firearm to hit what the shooter is aiming at. This is particularly true of rifles and the like that are expected to be fired at longer distances in situations where the impact of the fired bullets may shift due to such factors as gravity and wind that act upon the fired bullets. Many firearms have a fixed front sight with a variable rear sight that is adjustable for elevation and possibly also for windage. However, there are few firearms that have front sights that are adjustable for elevation.
The well known AR-15 or M-16 type or family of firearms is an example of a family or type that has an elevation adjustable front sight. The M-16 type front sight has an externally threaded lower conical portion that screws into a threaded hole in a sight base and the sighting elements is located on the outer end of the threaded portion. A circumferential flange with outer indentations is located around the base of the sight element and these indentations permit the threaded shaft to be rotated by the user by inserting the point of a bullet or the like into an indentation and then applying a lateral or rotatable force to cause the threaded shaft portion to be threaded into or out of the threaded hole in the sight base. When the threaded portion is threaded into the threaded hole, the front sight is lowered and the firearm will normally shoot higher. Conversely, when the threaded portion is screwed out of the threaded hole, the front sight is extended or elevated and the firearm will normally shoot lower.
It has been determined that it is beneficial to provide the shooter with two or more different front sight elements such as blades or posts. This gives the shooter a choice of front sight elements to suit his or her particular need or preference. For instance, a small blade type front sight might be desired for precision or target shooting but a larger size blade type sight might be desired for hunting game where speed is required and a larger sight is beneficial. Unfortunately, mounting such a dual convertible front sight on a rotating elevation adjustable front sight, so that it can be switched by the user, presents severe problems because, if the front sight is rotated to present a different front sight blade or the like, the rotation of the sight also moves the front sight up or down and this changes the point of impact of the bullet which is not acceptable.
This invention permits a rotatable elevation adjustable front sight to be used with a plurality of front sight elements such as blades, dots or the like without changing the elevation of the sight. Consequently, with this invention the shooter can readily change the front sight element to suit the particular shooting requirements without changing the point of impact of the bullets when the firearm is fired. In one embodiment of the invention a wide range of front sight elements can be readily substituted by the shooter. The front sight invention is capable of replacing the front sight in the M-16 type or family of firearms.